1. Technical Field
The present disclosure relates to a sewing machine provided with a needle plate detachably attachable to a bed thereof.
2. Related Art
A sewing machine includes a needle plate detachably attached to a bed thereof. The needle plate has a rectangular hole through which a feed dog is moved upward and downward so as to appear above and disappear below the needle plate and a needle hole through which a needle is passed. The rectangular hole is formed into such a size that the feed dog is movable therethrough. On the other hand, the needle hole is formed into such a size that a needle is passable therethrough during sewing, for example, in straight stitches or zigzag stitches. The needle hole is further formed so as to be as small as possible in order that workpiece cloth may be prevented from being pulled by a needle thereby to drop thereinto during sewing.
Some types of sewing machines are provided with a straight stitch needle plate and a zigzag stitch needle plate both of which are separate from each other. In this case, a user needs to selectively change between the straight and zigzag stitch needle plates. Furthermore, when carrying out a maintenance work for the sewing machine, the user sometimes detaches the needle plate. In re-attachment, the needle plate once detached needs to be attached to the bed so that the needle hole thereof accurately corresponds with a needle location. However, a clearance between the needle hole and the needle is small since the needle hole is small as described above. Accordingly, it is difficult to attach the needle plate to the bed so that the needle hole accurately corresponds with the needle location.
In view of the aforementioned difficulty, there is provided a sewing machine in which a location of the needle plate attached to the bed is adjustable. More specifically, the sewing machine is provided with an adjusting eccentric pin which is adjusted so that the needle plate is fixed to a bed frame (the bed) by a tension screw after a fixing point thereof has been fine adjusted. However, an adjusting work is troublesome in the above-described sewing machine. Accordingly, although it may be suggested to determine the fixing point of the needle plate only by the tension screw and to fix the needle plate to the bed, it is difficult to accurately determine the fixing point of the needle plate on the bed since a clearance (an allowance) is generally provided between the tension screw (a male screw) and a female threaded screw hole (a female screw).